XF 1.4 Users Banners won't get centered using mobile or tablet view (Responsive)

[CommanderMadi]

Howdy,

I searched about how to center the user banners and found this thread: https://xenforo.com/community/threads/center-all-banners-in-messageuserblock.81355/

I did the following edits but still no hope:

.Responsive .messageUserBlock .userBanner
    {
        max-width: 150px;
        border-top-left-radius: 3px;
        border-top-right-radius: 3px;
        position: static;
        display: inline-block;
        margin: 0 auto;
        text-align: center;
    }

What am I doing wrong?